Spark gap



Feb. 3, 1931. s. FLARSHEIM Y SPARK GAP Filed Oct. l26.- 1927 2 Sheets-Sheet 2 gnoznoz Patented Feb., 3, i931 rari' ics ED'WIN S, FLARSHEIM, OF CINCINNATI, OHIO, ASSIGNOR TO THE LIEBEL-FLARSHEIM COlllIPANY,Y OF CINCINNATI, OHIO, A CORPORATION F OI-IO SPARK GAP Application filed 0ctober'26, 1927. Serial No. 228,964.

rIhis invention relates to spark gaps and especially to spark gap mechanisms for therapeutic machines and the like Awherein the spark electrode spacing of the gap con- ,5 trols current characteristics of prime importance. One therapeutic machine of this type is disclosed and claimed by me in co-pending application, Serial No. 215,541.

in the case of a therapeutic machine for the application of high frequency current the spark electrode spacing determines the voltage of the current applied to the patient. It is therefore essential that the gap spacing be not subject to thermal changes which would vary the voltage of the applied current during a treatment.

llherefore, one object Vof the invention is to provide a spark gap wherein the spark electrode spacing is relatively constant over the temperature range to be encountered in service.

On a therapeut-ic machine for the application of high frequency currents it is advisable to have a plurality of gaps or opposing spark electrode sets.

rllherefore, another object of the invention is to provide a spark gap comprising a plurality of sets of opposing spark electrodes the spacing of each set independently adjustao able and all ofthe sets adjustable as to spacing as a unit, i. e., collectively.

Other ob'ects and certain advantages will appear in the description of the accompanying drawings forming a part of this specifiaa cation, in which: Y

Figure l is a front view of the spark gap device, showing a control mechanism at one end thereof. Y

Figure 2 is a sectional View taken on line lo 2 2, Figure l. Y

Figure 8 is an enlarged detail sectional view taken Online 3 3, Figure l, showing the relation of the radiator plates and the mounting therefor.

Figure 4; is a plan view of one end of the spark gap.

Figure 5 is a sectional view taken on line 5-5, Figure 4, showing the spark gap device in end view. Y

Figure 6 is a sectional view taken on line 6-6, Figure l, detailing the control for collective adjustment of the spark gap sets.

, This invention comprises opposing spark s electrodes andsupports therefor, the connection between the supports and spark electrodes preferably being made through flexible radiator plates.V Each spark electrode is recessed on the side toward the support or bar which carries it. Spacers are disposed between each spark electrode and its carrying support or bar. One end of each spacer is placed in a spark electrode recess and the other end contacts an adjustable abutment carried bythe bar. These spacers are of special alloy of steel or some other material, such as porcelain or fused quartz, possessed of a low or substantially zero coefficient of eX- pansion so that the electrode spacing does not change materially as the gap becomes hot.

More specifically, this spark gap device comprises a base l, and side standards or supports 2 mounted at either end of the base. At th-e top of each standard is bolted an inwardly extending bracket 3 to which bracket is attached a stationary gap bar 4 preferably of marble, porcelain orsome other insulating material. The connection betweenthe gap barf and brackets 3 is made by means of shoulder screws 5 extending through the bar and through the brackets, the bar being positioned on the shoulder screws by means of nuts and Washerson either side of the bar, the shoulders 6 of said screws which rest upon the brackets, being riveted to the brackets on the sides opposite to the shoulders, and providedfwith eyelets 7 at their ends on the other sides of said brackets. Pivoted to the inner faces of said side standards by means of studs 8 projecting from said facesis a yoke'9. This yoke consists of a rod l0 extending substantially the distance of the standard spacing and arms ll eX- tending from the ends of the rod l0. lt is these arms which are pivoted to the side standards, the pivot points being located near the ends of the arms. Pivoted to the ends of the arms by means of pins 12 extending inwardly from the arm ends are slide bars 13 held in position on the studs by cot-ter pins. The opposite ends of these slide bars 13 are slotted and the slots are entered by studs 14 extending` inwardly from the side standards. By this construction the swinging of the yoke upon its pivots back and forth reciprocates the slide bars 15 in substantially a straight line. The mechanism for adjusting the yoke will be described further on. in the description. `Gn the inner faces :of the slide :bars 13 .are riveted brackets 15 to which a movable gap rbar le is secured by means of shoulder screws 17 such as used on the stationary gap bar. stud 18 is provided on each of the brackets 15 having an eyelet disposed 1in alignment with the eyelet 7 extending below the opposing face of the stationary gap bar retaining brackets. A. coil spring 19 under tension anchored at each end in these eyelets in order to draw the gap bars together.

These gap bars l and 1G carry a plurality of opposing sets of spark electrodes .20, five sets as disclosed. Each set of opposing spark electrodes comprises opposing spark electrodes proper 21, each connected to its carrying gap ha r `by Way of a plurality of radiator plates 22 of which one or more .are ilexible. These s ark electrodes 2l are preferably tipped with tungsten or some other .substance suitable for spark gap purposes. They are recessed as at 23 on the side opposite to the active face, said recesses extending almost to `said active face and leaving "but a thin partition of metal between 'the recess and the active face. The radiator plate 2st adjacent the spark electrode is apertured and the electrode riveted to the plate through said aperture.

As disclosed, four radiator' plates 22 are used in connection With each spark electrode. The radiator plate 25 adjacent to the gap bar is riveted to the adjacent radiator plate at the corners by means of shouldered studs 26. This radiator plate 25 is of thinner material than the others to provide spring action. The three radiator plates nearest to the spark electrode are held together by means of spacing Washers 27 with an cyelet 28 running through and spread on each end. These spacing washers and eyelets are ldisposed relatively near the centers of said radiator plates. Due to the disposition of the mounting studs of the radiator plates the three inner radiator plates are substantially rigidly secured together, moving as a unit in relation to or under the flexing of the spring radiator plate 25. All of the radiator plates are provided With apertures 29 aligned with the spark electrode recesses.

In the gap bar behind and in alignment with the apertures is mounted a sleeve B1 flanged on the inner side of the gap bar, threaded on the outer side ot the gap bar and secured thereto by means of a nut and Washer. 4ln the outer end ott Jthis sleeve S1 is a set screw or adjustable abutment 32 lor la spacer rod 33 which extends from within said sleeve through the apertures in said radiator plates Which are siiiliciently large to provide clearance and into the 'liar end of the recess of the spark electrode. The set 'screw issecured by means of'a nut 32 engaging the outer end of the sleeve. lherefore, by screwing in or out this set screwv the spacer rod 33 is .moved longitudfinally and the distance `or' the spark lelectrode trom the grap bar carrying it correspondingly adjusted. The requisite amount of motion is permitted by the flexible radiator plate adjacent to the gap bar.. It is therertore possible by adjusting this set screw to adjust each spark electrode individually in relation to the gap lrbar and bring them into proper align-ment. T he spacer 'rod is preferably of special alley 'of steelor Vsome other material having substantially zero cocilicient of thermal eXpan sion within the temperature range encountered inservice. lli at little expansion there might be in the spacer rod is'compensated 'for by the very slight expansion of the sleeve 3l extending through the vgap bar. "lhesc spark electrodes are so adjusted that theiiexible radiator plate is under tension greater than can be relieved by expansion -olf the radiator plates and the electrode thus held firmly against the spacing member se that only the expansion of this lspacing` member Iin relation to its yadj ustable abutment changes lor alters the position of the spark electrode in relation to its lcarrying liar. Therefore va spark gap compri-sing tivo ot these spark electrodes so mounted is not subject to Achange or alteration of gap distance as the temperature varies as a result of the heat generated by the spark.

These individual sets `of spark electrodes are connected in series by means ci licxible connectors 34 (indicated diagrannnatically in Figure extending between and seeuret'l to the radiator plates.

The mechanism for collectively controlling the plurality of spark gap 20 is ar ranged as follows:

The rod 1() of theadjustment yoke if) extent out 'beyond the end bracket 2 and has a link 35 pivotally secured thereto. The other end of the link 35 pivotally connected to the end of a lever 36 fulcrumed at 37. 1The 'fulcrum point 37 'jor the lever 36 is the loose end of an arm 38 attached to the inner end -ot' a sleeve 39 pivot-ally mounted on a stud V4:0 -eX- tending from the end frame 2. The outer end of the sleeve v39 has an arm 41 secured thereto, the outer end of the arm 41 providing a yoke pivotally mounting a block 12.

rlhe block 4:2 Vhas an adjustment sleeve el?) threaded therethrough, and a rod 3i-i extends through the sleeve, 'the louer end 'of the rod 44 being provided with a :radiallyT disposed pin engaging in a slot at the base end of the sleeve 43, lthe upper end or' the rod del being adjustably mounted in the provided with a knob 45, this knob being hung or seated on an inclined seat 46 in the trame 47.

Raising or lowering the knob 45 sw ings the adjustment yoke carrying the movable bar 1G by raising or lowering the tulcrum point of the lever 36. 'l his movement gives a very coarse and rapid adjustment. rllhe arrangement of the pin and slot permits loweringoi" the knob and rod 44 independently oi the linkage and adjustment bar in the event that the gaps are held apart otherwise for cleaning, etc. lotation ot the knob raises and lowers the block 43 through the threaded sleeve providing an intermediate form of adjustment. For a more minute or delicate adjustment a bell crank lever 48 is pivoted to the end trame 2 and has one arm thereof provided with a pin engaging in slotted end of the lever 36. rEhe bell crank lever may be rocked by any suitable n'ieans, this rocking swinging the lever 46 on its iiul'crum through a comparatively small range of.

movement, this beingl reduced considerably in its application to the link 35 by means of the positioning or the tulcrum point of the lever 86.

By this arrangement of linkage, three means for collectively adjusting the spark gap sets are provided, First, a minute or line adjustment through the bell crank lever. Secc-nd, an intermediate adj ustment through rotation or" the knob, raising or lowe ig the block 42, and third, a very rapid ustment or separation of the sparkgap electrodes by raising or lowering the knob.

Claims on this mechanism for collectively adj usting' the spark gap are made in a separate application.

Having described my invention, l claim z' l. A spark gap mechanism, vvcomprising, two gap bars, opposing spark electrodes carried by said gap bars, said spark electrodes recessed each on the side toward the carrying bar, each recess extending almost to the sparl discharge tace leaving only a thin partition or metal between the recess and the lace, and spacers possessed of substantially Zero coer'licient of expansion extending between each spark electrode and its carrying bar each spacer being disposed within the recess or' the spark electrode which spaces Jfrom the bar.

2. A spark gap mechanism, comprising, two gap bars, opposing spark electrodes carried by said gap bars, flexible heat radiating plates connecting said spark electrodes tosaid bars, and spacers possessed of substantially Zero coellicient of expansion be weon the spark electrodes and the bars, spacer' at one end and in a recess ot a spark electrode at the other end to space said bars and electrodes any distance desired.

- 3. A spark gap mechanism, comprising, two side supports, a gap bar secured to said ser side supports, a yoke pivoted to said side supports, a slide bar pivoted to said yoke arms, a second gap bar secured to said slide bars and adapted to be adjusted in relation to saidjtirst gap bar by movement of the yoke, and opposing spark electrodes carried by said gap bars.

4. A spa-rk gap mechanism, comprising, two side supports, a gap bar secured to said side supports, a yoke pivoted to said side sup- Y portsyslide bars pivoted to said yoke arms,

guides on the side supports for said slide bars,

a second gap bar secured to said slide bars and adapted to be adjusted in relation to said first gap bar by movement of the yoke, and

opposing' spark electrodes carried by said bars.

5. A spark gap mechanism, comprising, opposing spark electrodes, supports for said spark electrodes, lexible radiator4 platessecuring said spark electrodes to their supports, and steel spacing members having substantially Zero coeiiicient of expansion determining tlie distances of said electrodes from their supports, said spacing members passing loosely through said radiator plates and shielded thereby from the spark heat.

6. A spa-rkv gap mechanism, comprising, two side supports, a gap bar secured to said side supports, a yoke pivoted to said side supports, slide bars pivoted to said yoke arms, guides on the side supports for said slide bars, a second gap bar secured. to said slide bars and adapted to be adjusted in relation to saidtirst gap bar by movement of the yoke,

` opposing spark electrodes carried by said gap bars, and means maintaining the spark electrode spacing constant despite thermal changes. j

7. A spark 'gap mechanism, comprising, a plurality of sets of opposing rearwardly recessed spark electrodes, supports for said spark electrodes, flexible radiator plates securing` said spark electrodes to their supports, spacing members entering the spark electrode recesses, said members determining the distances of said electrodes from their supports, said spacing members passing loosely through said radiator plates and shielded thereby from the spark heat, means 'for altering' the spacing of each opposing set of electrodes, andmeans for altering the spacing of said sets collectively.

8. A spark gap mechanism, comprising, a base, two side supports mounted on said base, a stationary gap bar secured to said side supports, a second gap bar movable relative to the said stationary gap bar, slide bars guided on the side supports and supporting said movable gap bar, a yoke having its arms pivoted to said side supports and to said slide bars7 said yoke adapted to adjust the relative position ot the gap bars by its own pivotal movement, opposing spark electrodes carried by said gap bars, heat radiating plates securing said electrodes to said bars, sleeves in said gap bars, one positioned behind each electrode, set screws in the outer ends of said sleeves, deep recesses in the backs of each of said spark electrodes, leaving 4but a thin partition of metal between the recess and the spark electrode face, and steel spacing members having substantially zero coefficient of expansion extending between the ejap bars and the spark electrodes, one end of each spacing member being disposed in a spark electrode recess and the other end in a sleeve carried by a gap bar, said end abutting the set screw carried by the sleeve to provide individual spark electrode adjustment.

9. The spark gap mechanism, comprising, spark electrodes opposingly disposed to constitute a spark lgap, supports for said spark electrodes, a spacing member possessed of substantially zero coefficient of expansion betwn each spark electrode and its support, said spacing member adapted to determine the minimum distance between the electrode and its support, and flexible means connecting each spark electrode to its support said means adapted to insure that this minimum distance be not exceeded.

10. A spark gap mechanisn'n comprising, two relatively movable bars, a plurality of opposing spark electrodes flexibly secured to said bars, and adjustable members possessed of substantially zero coel'licient of expansion disposed between each spark electrode and the supporting bar, said members adapted to determine the spacing of the spark electrode from its supporting bar.

11. A spark gap mechanism, comprising, two opposing supports, two opposing spark electrodes, each iexibly attached to one of the supports, and two spacingr members possessed of a substantially zero coeiicient of expansion, each spacing member mounted between a spark electrode and its support, and means located in said supports for adjusting said spacing members to and from said supports to determine the distance of each spark electrode from its support.

12. A spark gap mechanism, comprising, two relatively movable bars, spark electrodes carried by said bars and arranged to constiw tute a plurality of spark gaps, spacing members having substantially zero coefficient of expansion disposed between each spark electrode and the bar carrying it to determine the distance of the spark electrode from. the bar, and means remote from the zone oit heat created by the action of the spark gaps for regulating the distance between the bars supporting the electrodes.

In witness whereof, I hereunto subscribe my name.

EDWIN S. FLARSHEIM. 

